Since as I'm reading it, a force 6 spirit seem almost invulnerable to anyone not using an assault cannon. I'm basically wondering how you'd optimize someone to take out spirits, beyond the obvious of being a mage.
Called Shot bonuses actually apply, and the bonus DV from getting net hits on the attack roll, and the AP from weapons.
So let's say that you pull a called shot from an assault rifle firing AP rounds. The base DV is 6, up by +4 for the called shot, + at least one more for hitting at all, you've got a modified DV of 11 (or more) and you are subtracting 5 from the armor at the other end. So Immunity to Normal Weapons does nothing to you if you are throwing down against a spirit of Force 7 or less. If you get a second net hit, you'll sail through a Force 8.
Then you apply the burst damage bonus after the comparison, by that's fine because you're already killing them pretty good.
What combination of metamagic/spells should I pick up like the quickness if I want:
A.) Power that won't draw the attention of the authorities and is hard to take away from me.
B.) Raw power.
Masking. Extended Masking. Flexible Signature.
Building your own foci: Worth it?
Usually no. Foci are so expensive to bond that the slow trickle of foci that you find on the dead bodies of enemy spell casters is actually more than you want or need.
But your gamemaster probably doesn't throw in weapon focus monowhips or laser guns, so if you want to have a weapon focus, you'll probably have to make it yourself. Carrying around a spear is straight up chickenshit malarky.
What cyberware/bioware should a mage seriously consider setting fire to his/her essence for?
Enhanced Senses and Datajacks. Seriously, you can target people you can "see", so getting vision enhancers is totally worth a Magic point.
Also, if I'm making a possession tradition from scratch, what combination of spirits should I pick up for raw cheesy power?
Task, Guardian, Guidance, Man, Water.
Seriously, that's straight up Voodoo. It's already about as awesome as it is possible to be. You get both skill choices, you get the divination, you get the weather control, and you get the spell hand-off cheese.
There are some crazy awesome options available to people with Invoking - Regeneration and Quake are no joke. But short of that, the basic Houngan has about the best spread of unique spirit talents that it is possible to have on a possession tradition (recalling for the moment that the draw on Air and Earth spirits is largely related to their physical attributes which a Possession tradition can't even use).
But of course, what you really want to do is go Toxic and just make up five spirits that all do something awesometastic.
-Username17